looking for help with base rigging a game model
It looks like you might need to start with some re-topology or a decimation modifier first. Lower the poly count so the engine can cope with your model, if it's not for a rendered cut scene that is.  
Next Add some bones, the first bone must be created in
object mode (Tab), add a armature bone (Shift + A, A, S).  

To keep the bones visible in front of your mesh, select a bone then go to the
Properties panel, Object Data tab, Display drop menu, TICK In Front.  

In edit mode: Extrude bones (E), Parent bones (Ctrl + P), Clear Parent Bones (Alt + P) 
or
add bones (Shift + A).  
Parent the object (mesh) to the armature (Bones): Select the object, and the armature together 
(Shift + LMB) and parent them with automatic weights (Ctrl + P, I).